A superdeformed (SD) band has been identified in a non -alpha -conjugate nucleus 35 Cl. It crosses the negative parity ground band above 11/2 − and becomes the yrast at 15/2 − . Lifetimes of all relevant states have been measured to follow the evolution of collectivity. Enhanced B(E2), B(E1) values as well as energetics provide evidences for superdeformation and existence of parity doublet cluster structure in an odd-A nucleus for the first time in A≃ 40 region. Large scale shell model calculations assign (sd) 16 ( The superdeformed bands observed in the even-even nuclei in upper sd shell have provided favourable condition to describe the collective rotation microscopically involving the cross-shell correlations [1,2]. Complementary descriptions in terms of particle-hole excitations in the shell model [2,3], and α-clustering configurations within various cluster models [4][5][6] have been utilised to interpret the data. Till now no such band has been observed in non -alpha -conjugate odd-A, N =Z isotopes in this region [7]. If a nucleus clusterizes into fragments of different charge to mass ratios, the center of mass does not coincide with its center of charge. As a result a sizeable static E1 moment may arise in the intrinsic frame [8], resulting in several distinctive features in the spectra. Two adjacent opposite parity deformed ∆I = 2 bands connected by strong E2 intra-band transitions in turn are connected by strong E1 inter-band transitions [8] forming an apparent ∆I = 1 rotational band with alternating parity states. Since early seventies [9][10][11], a number of similar alpha-cluster bands have been studied extensively. In the spectrum of 19 F , cluster-model calculations have shown that coupling of a proton hole in the p shell coupled with four nucleons in the sd shell (a proton hole coupled to 20 N e) gives rise to alpha-cluster bands. The lowest alpha + 15 N parity partner bands built on K π = 1/2 + ground-state band, lowest lying famous K π = 1/2 − at 110 keV and some other bands lying above 5 MeV have been observed. So far no similar clustering have been observed in odd A nuclei in the A≃ 40 region, where evidences of clustering have been manifested in even-even nuclei through superdeformation.According to Ikeda [12], in the spectra of light nuclei, cluster like configurations would appear near the threshold energy needed for breakup into proper sub-nuclei. For the nucleus of our interest 35 Cl, the threshold energy [13] to appear as a composite of 32 S and a triton (t) ( 32 S + t) is around 18 MeV. On the other hand, threshold for the decay of the composite system 35 Cl into ( 31 P + α) clusters is around 6.5 MeV. The SD rotational band observed in 36 Ar has been shown to have cluster structure. So one may expect to find deformed cluster bands in the excitation spectra of 35 Cl also generated by coupling a proton hole to SD states in 36 Ar. In this letter, we report the observation of a superdeformed band for the first time in the odd A 35 Cl isotope. The reduced transition probabilities for all...

No abstract

No abstract

No abstract

High-spin states in 120 Te were populated in the reaction 80 Se( 48 Ca, α4n) 120 Te at a beam energy of 207 MeV and γ-ray coincidences were measured using the Gammasphere spectrometer. The previously known level scheme is extended to higher spin and new interband transitions and sidefeeding branches are established. Five highly-deformed rotational bands, extending up to almost I = 50, are observed for the first time. The bands are compared with similar structures found recently in neighboring nuclei. The experimental results are interpreted within the framework of the cranked Nilsson-Strutinsky model. Configuration assignments to several terminating states and to the high-spin bands are discussed.

High-spin spectroscopy of I-122Singh, Purnima; Nag, Somnath; Selvakumar, K.; Singh, A. K.; Ragnarsson, Ingemar; Bisoi, Abhijit; Goswami, A.; Bhattacharya, S.; Kumar, S.; Singh, K.; Sethi, J.; Saha, Sudipta; Trivedi, T.; Jadhav, S. V.; Donthi, R.; Naidu, B. S.; Palit, R.High-spin states in 122 I have been investigated using the 116 Cd( 11 B,5n) 122 I reaction at a beam energy of 65 MeV and γ -ray coincidence events were recorded with the INGA spectrometer. The level scheme of 122 I has been extended up to spin I = 30. Experimental features, such as band-crossing frequencies, aligned angular momenta, signature splitting, and B(M1)/B(E2) ratios have been used for configuration assignments to low-energy band structures. Maximally aligned states involving all eight particles outside the 114 Sn core and states with one particle antialigned have been identified. Cranked Nilsson-Strutinsky calculations have been used to interpret high-spin structures.

No abstract

Lifetimes of the states in the quadrupole structure in 143 Eu have been measured using the Doppler shift attenuation method and the parity of the states in the sequence has been firmly identified from polarization measurements using the Indian National Gamma Array. The decreasing trends of the deduced quadrupole transition strength B(E2) with spin, along with increasing J (2) /B(E2) values before the band crossing, conclusively establish the origin of these states as arising from antimagnetic rotation. The abrupt increase in the B(E2) values after the band crossing in the quadrupole band, a novel feature observed in the present experiment, may possibly indicate the crossing of different shears configurations resulting in the re-opening of a shears structure. The results are reproduced well by numerical calculations within the framework of a semi-classical geometric model.